4-1/2", PVC, Sewer, Kitchen and Bath Relief Valve

Releases Waste to Outside of Buildings in the Event of Sewer Line Blockage, Preventing Costly Damage Due to Sewage Backflow or Overflow; Automatic Unlock and Re-Lock; Vandal Resistant; Safe in Yard or High Traffic Areas; Solvent Welds Over 4 Inch Schedule 40 DWV Pipe; Made in USA